The present invention relates to a solar energy system and more particularly, relates to a solar energy system in which solar energy derived from the sun may be stored for later use, for example, at times when it is not possible to expose the solar energy collectors to direct sunlight.
The growing demand for energy of all types, including electrical energy, has driven up the price of energy and has placed it at a premium. For various reasons, the search for new sources of energy has not kept pace with the growing demand. In addition, price fixing agreements by foreign oil cartels have greatly increased the price of oil imported from those countries and has also driven up the price of all fossil fuels, even those produced entirely in the United States.
In the past, cheap and plentiful fossil fuels eliminated the necessity of developing solar energy as a substantial source of the energy needs of the country. However, with the dramatic increases in the cost of fossil fuels, and in some cases, the complete lack of such fuels to meet the total demand, other sources of energy have become a necessity. For various reasons, nuclear energy has not, and in all probability will not, completely fill the gap between the demand and supply for energy.
Although it has been known for some time that sunlight or radiation from the sun may be converted into electrical energy by means of various photo-voltaic or solar cells, such as silicon crystals and various thin films, one of the problems in the development and use of solar energy systems has been the fact that the solar energy is not always available. For example, solar energy is not available during the hours of darkness and also may not be available even during the daylight hours where it is heavily overcast or when precipitation exists. Therefore, it is necessary to provide a means of storing the energy derived from the sun during the periods when solar radiation is available in order to provide energy at times when solar energy is not available.
U.S. Pat. No. 3,892,433 discloses a hydro-electric generation plant in which electrical energy generated by a steam turbine driven generator is used to pump water from a low elevation reservoir in the hydroelectric plant to a higher elevation storage reservoir. The steam turbine is driven by steam boiler-super heater which is heated by solar radiation. However, this patent does not disclose a mechanical energy storage system in which solar energy is converted into electrical energy and used to drive an electrical means for storing energy in a mechanical energy system, such as a compressed air system, a combination of compressed air and resilient means system or a gravity energy system.